The three hypotheses that explain why being born in the United States
leads to a higher chance of developing allergies include the following:
The weather patterns in the United States bring more allergens compared to other countries.Other factors which might influence why there are more children with allergies in the United States include climate, obesity, and the typical western diet with high amounts of processed foods.The hygiene hypothesis claims that children in the United States are not exposed to enough germs in their infancy and childhood to develop their immune system‘s properly.Allergies are caused by a host of factors such as :
ClimateDietImmune systemThese factors is the reason why the chosen hypotheses are the most
appropriate.
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how many moles are in 8.32 × × times 10^24 molecules of co2?
Answer:
13.8 moles
Explanation:
You know that in a mole you have 6.022x10²³ something in this case of molecules. By knowing that by each mole you have 6.022x10²³ molecules, then you can establish the factor of conversion:
8.32x10²⁴molec of CO2 x 1 mol/6.022x10²³ molec of CO2
You divide 8.32x10²⁴/6.022x10²³ and you get 13.81 moles.
Find the percent composition of OXYGEN in Manganese (III) nitrate, Mn(NO3)3.
Answer:
59.8%
Explanation:
First find the Mr of manganese (III) nitrate.
Mr of Mn(NO₃)₃ = 54.9 + (14 × 3) + (16 × 3 × 3) = 240.9
Since we have to find the percentage composition of oxygen, we need to find the Mr of oxygen in the compound, which is:
Mr of (O₃)₃ = (16 × 3) × 3 = 144
Now we can find percentage composition / percentage by mass of oxygen.
% composition = [tex]\frac{Mr\ of\ oxygen\ in\ compound}{Mr\ of\ compound}[/tex] × 100
% composition = [tex]\frac{144}{240.9}[/tex] × 100 = 59.776%
∴ % compostion of oxygen in maganese(III)nitrate is 59.8% (to 3 significant figures).
If the temperature changes by 100 K, by how much does it change in degrees Celsius?
A. 0 degrees Celsius
B. 100 degrees Celsius
C. 37 degrees Celsius
D. 273 degrees Celsius
Taking into account the degrees Celsius and Kelvin, if the temperature changes by 100 K, by 100 degrees Celsius it change in degrees Celsius.
A degree Centigrade is a unit of temperature (the physical quantity that reveals the level of heat) whose symbol is °C.
On the other hand, the degree Kelvin, whose symbol is K, is the unit of temperature on the scale created by William Thomson Kelvin, in 1848, based on the degree Celsius, he established his zero point (0) at zero absolute (-273.15 ° C). The figure 0 K is equivalent to the theoretical point where gases have no volume. Absolute zero or 0 K is the point where molecules theoretically stop moving. It is the "perfect" cold.
Considering that zero on the Celsius or degrees centigrade (0 ° C) scale is defined as the equivalent of 273.15 K, the conversion from degrees ° C to K is carried out using the following expression:
T(K)= T(°C) + 273.15 K
In this case, if the temperature changes by 100 K, as it is a change in temperature, the numerical value in K units is the same in ° C units.
Then, the correct answer is option B. if the temperature changes by 100 K, by 100 degrees Celsius it change in degrees Celsius.
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Write the correct IUPAC name for the following compound
Answer:
2-ethly-3-5 dimethylheptam
Explanation:
trust meeeeee
which of the following best describes a single replacement reaction?
two elements combine to form a compound
one element takes the place of another in a compound
two elements switch places in a compound
a compound breaks into separate elements
Answer:
One element takes the place of another in a compound
Explanation:
I just took a test for it and got it right. :)
Hope This Helps :)
Speed is the rate of change of position expressed as _____ traveled per unit of time.
Answer:
distance traveled per unit of time.
what is the molarity of a koh solution if 25.0 ml neutralizes 35.0 ml of a 0.200 m hcl solution?
If 25.0ml neutralizes 35.0 ml of a 0.200M HCl solution, the molarity of KOH solution is 0.28M
The reaction between KOH solution and HCl is written below.
[tex]HCl + KOH \rightarrow KCl + H_2O[/tex]
Volume of KOH, [tex]V_B[/tex] = 25.0 ml
Volume of HCl, [tex]V_A=35.0 ml[/tex]
Molarity of HCl, [tex]C_A=0.200 M[/tex]
Molarity of KOH, [tex]C_B=?[/tex]
Number of moles of HCl, [tex]n_A=1[/tex]
Number of moles of KOH, [tex]n_B=1[/tex]
The mathematical equation for neutralization reaction is:
[tex]\frac{C_AV_A}{C_BV_B} =\frac{n_A}{n_B}[/tex]
Substitute [tex]C_A=0.200 M[/tex], [tex]n_A=1[/tex], [tex]n_B=1[/tex], [tex]V_B[/tex] = 25.0 ml, and [tex]V_A=35.0 ml[/tex] into the equation above in order to solve for [tex]C_B[/tex]
[tex]\frac{0.2 \times 35}{C_B \times 25}=\frac{1}{1} \\\\25C_B=7\\\\C_B=\frac{7}{25} \\\\C_B=0.28M[/tex]
Therefore, the molarity of KOH solution is 0.28M
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How do chemists predict the shapes of molecules?
Due to the repulsion between electrons, valence electrons will be arranged as close to each other as possible.
Due to the attraction between electrons, valence electrons will be arranged as close to each other as possible.
Due to the repulsion between electrons, valence electrons will be arranged as far apart from each other as possible.
Chemists can't predict the shape of molecules, because the attractive forces between valence electrons are unpredictable.
A. Due to the repulsion between electrons, valence electrons will be arranged as close to each other as possible.
The approximate shape of a molecule can often be predicted by using what is called the valence-shell electron-pair repulsion (VSEPR) model.Electrons in bonds and in lone pairs can be thought of as a charge cloud that repels one another and stay as far apart possible, thus causing molecules to assume specific shapes.The shape of a molecule is determined by the location of the nuclei and its electrons.Therefore, the correct option is A.
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according to iupac nomeclature rules which set of chemical name and formula for the same compound is correct?
Answer:
stock and traditional
Explanation:
the iupac says so
Hey y’all is these answers correct?
Answer:
ʏᴇs, ɪ ᴛʜɪɴᴋ
Explanation:
TᕼᗩᑎKՏ ᒪOᗪՏ
Part A
Before you design your model village, write down the problems you observed in task 1. What were the largest risks to the community? What happened to the homes?
The largest risks while designing a model to withstand a village include that the model does not mitigate the effects of the tsunami or only mitigates the effects partially, which would cause damages to the homes.
Designing a model to withstand the effect of any natural phenomenon such as an earthquake, fire or tsunami is not an easy task and will require the following cycle:
Designing the model.Testing the model.Making changes or designing a new model.In the case of a model for tsunamis, it is likely the following problems occur:
The model does not protect the houses from tsunamis.The model does not protect the houses completely.This would lead to negative effects such as:
Damages in the houses.Dead or injured people.Destruction of infrastrcture.Note: This question is incomplete because the context is missing; here is the missing part.
Protecting Your Model Village from Tsunamis this task, you will design a model village to withstand the effects of a tsunami.
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Which of the following has mass?
A. Space
B. Light
C. Matter
Ο Ο
D. Force
Answer:
matter should be the answer
Explanation:
Hope this helps!
Answer:
matter because matter makes up everything in the world EVERYTHING like this computer ri am typing on? matter. what ever device you are using to view this? matter. everything is made of matter. matter is starting to sound weird now so I'm gonna stop saying it and this is the end of the answer remember THAT ANSWER IS MATTERR!!!!!
where does oxidation occur in an electrochemical cell
according to the arrhenius concept, if naoh were dissolved in water, it would act as
Answer:
base
Explanation:
The substance NaOH will be disassociated in ions of Na and OH.
Ahrrenius concept of base it's anything that dissolved in water produces OH.
Why were your results for the Southern Hemisphere opposite of what you found for
the Northern Hemisphere?
1. One atom contains 29 protons and 34 neutrons. Another atom of the same element has a mass number of 65. How many protons and neutrons does this unknown atom have?
A. 28 protons, 37 neutrons
b. 29 protons, 36 neutrons
C. 29 protons, 35 neutrons
D. 31 protons, 34 neutrons
Answer:
b
Explanation:
because its the atom of the same element, the no of protons doesn't change but the mass number changes so we can find the mass number by:
(mass number = atomic no/no of protons + no of neutrons)
here;
mass number given = 65
and we know, no of protons = 29
let no of neutrons = x
hence,
65 = 29 + x
x= 65 – 29
x= 36
hence your answer is b
why is it hotter in the summer and colder in the winter?
Answer: During the summer, the sun's rays hit the Earth at a steep angle. ... Also, the long daylight hours allow the Earth plenty of time to reach warm temperatures. During the winter, the sun's rays hit the Earth at a shallow angle. These rays are more spread out, which minimizes the amount of energy that hits any given spot.
name a metal and non metal which are liquid at normal pressure and temperature
Answer:
metal : Mercury(Hg)
non metal : bromine (Br)
Explanation:
mercury is liquid at room temperature and pressure and the same as bromine
Question 20 0/1 pts What is the frequency of a light wave with the wavelength of 680 nm? 'Reminder: the speed of light is 3.00 X 10 m/s
Answer:
[tex]4.4*10^{14}[/tex]Hz
Explanation:
what is the equilibrium concentration of co at 1000 k?
Answer: For the reaction, K c = 255 at 1000 K. If a reaction mixture initially contains a CO concentration of 0.1550 M and a Cl 2 concentration of 0.171 M at 1000 K. 1.
Explanation:
significance of symbol Mg
Answer:
Magnesium Magnesium is used in products that benefit from being lightweight, such as car seats, luggage, laptops, cameras and power tools. It is also added to molten iron and steel to remove sulfur. As magnesium ignites easily in air and burns with a bright light, it's used in flares, fireworks and sparklers.I hope this helps you !!has an atomic number of 1.
There are many with atomic number 1
hydrogen , helium , lithium , beryllium etc.
Hope this answer helps you dear!.
Answer:
With atomic number 1 is hydrogen
Explanation:
The valence with 1 is hydrogen, lithium.....
Which of these substances are greenhouse gases? Check all that apply. Oxygen carbon dioxide helium methane nitrous oxide.
The greenhouse gases are carbon dioxide, methane, and nitrous oxide.
The greenhouse effect has been defined as the entrapment of the sun's energy by the gases that result in the earth becoming warmer and a better place to live.
The gases present in the atmosphere that has been able to entrap the heat energy has been termed the greenhouse gases.
The greenhouse gases have been carbon dioxide, methane, and nitrous oxide.
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Answer:
carbon dioxide, nitrous oxide, methane
Explanation:
Mendeleev's arrangement of the periodic table was in order of increasing ____.
A. atomic number
B. atomic mass
C. neutron number
D. valence electron number
Answer:
B. atomic mass
Explanation:
He arranged the elements into rows in order of increasing mass so that elements with similar properties were in the same column.
State of Matter refers to _______.
Answer:
matter refers to anything that has mass and volume which occupies space
what are subatomic particles?
Explanation:
a particle smaller than an atom (e.g., a neutron) or a cluster of such particles (e.g., an alpha particle).
Passing an electric current through a sample of water (H2O) can cause the water to decompose into hydrogen gas (H2) and oxygen gas (O2) according to the following equation. 2H2O Right arrow. 2H2 O2 The molar mass of H2O is 18. 01 g/mol. The molar mass of O2 is 32. 00 g/mol. What mass of H2O, in grams, must react to produce 50. 00 g of O2? 14. 07 23. 05 28. 14 56. 28.
The mass of water decomposed to produce 50 g oxygen has been 56.28 g. Thus, option D is correct.
The reaction for the decomposition of water has been:
[tex]\rm 2\;H_2O\;\rightarrow\;H_2\;+\;O_2[/tex]
From the balanced equation, 2 moles of water decomposes to form 1 moles of hydrogen and 1 mole of oxygen.
The mass of oxygen produced has been 50 g. The moles of oxygen has been given by:
[tex]\rm Moles=\dfrac{mass}{molar\;mass}[/tex]
The moles of oxygen has been:
[tex]\rm Moles_O_2=\dfrac{50}{32}\;mol\\Moles_O_2=1.5625\;mol[/tex]
The moles of oxygen produced has been 1.5625 mol.
The moles of hydrogen decomposed has been given from the balanced chemical equation as:
[tex]\rm 1 \;mole\;O_2=2\;mole\;H_2O\\1.5625\;mol\;O_2=1.5625\;\times\;2\;mol\;H_2O\\1.5625\;mol\;O_2=3.125\;mol\;H_2O[/tex]
The moles of hydrogen decomposes has been 3.125 mol.
The mass of hydrogen decomposed has been given by:
[tex]\rm Mass=moles\;times\;molar\;mass\\Mass_{H_2O}=3.125\;\times\;18.01\;g\\Mass_{H_2O}=56.28\;g[/tex]
The mass of water decomposed to produce 50 g oxygen has been 56.28 g. Thus, option D is correct.
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How is a stable hydrogen atom different from every other atom?
Answer:
a hydrogen atom contains only one proton in it's nucleus, while atoms of all other elements contain more than one proton
Brainliest plzz
Why is it important to be careful when walking on an icy sidewalk?
Ice moves faster than you do.
There is less friction on an icy surface.
Ice is heavier than you, so it is a greater force.
none of the above
Answer:
The is less friction on an icy surface
Explanation:
This is because when u walk on plain ground there is steady friction on the surface but when u walk on an icy floor these is barely any friction which is why it's hard to walk on.
Answer:
There is less friction on an icy surface.
Hope that helps.
Explanation:
Pls Help Me (20 Points)
In one to two sentences, explain how to compare the strength of electrostatic forces between molecules in salt water to the strength of electrostatic forces between molecules in freshwater. Include a description of the data to be collected and how that data would allow one to draw conclusions about the relative strengths of the electrostatic forces in the two substances.
Answer:
-Salts are composed of ions that form a tightly packed and ordered network, which is called a crystal lattice, and it is held together by ionic bonds.
Explanation: salts are ionic compounds, which are composed by oppositely charged ions (cations and anions) which are bonded each other by ionic bonds, in an ordered arrangement, often a crystalline solid.
-When a salt is added to a polar solvent like water, the ions interact with the solvent molecules via ion-dipole forces, which overcome the forces originally holding the ions together.
Explanation: the molecules of a polar solvent are dipoles because they have dipolar momentum (a difference in charge due to a electronegativiy difference). When a salt is dissolved in a polar solvent, it dissociates in ions. So, the resulting interactions between these species are ion-dipole forces.
-The ions are then isolated and stabilized in solution via these interactions, and when this occurs for most of the salt compound, it is considered soluble in that solvent.
Explanation: the ions in solution are surrounded by solvent molecules which stabilizes them. A salt which is enterely dissolved in a solvent is soluble in that solvent.
-Due to the nature of the interaction between ions and solvent molecules, a concentration of ions can be dissolved higher in water than in alcohol.
Explanation: water molecules have unique properties that make water an universal solvent. Due to these properties and its polarity, water can dissolve larger quantities of salt than other polar solvents such as alcohol.
The electrostatic force in water without salt is stronger as compared to the water due to the presence of free electrons.
In water hydrogen bonding is present that is the only kind of electrostatic force present in the water. In water containing salt sodium and chloride ions are present which conduct strong electrostatic force. A static meter is ideal for measuring the of liquids. It measures the charge on the liquid. Hence, the electrostatic force in salt water is stronger as compared to the water due to the presence of free electrons.Learn more about electrostatic:
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